This invention generally relates to a unique method of welding a terminal to a wire in a flat flexible cable.
Flat flexible cables are used in wiring harnesses for vehicles. They are usually used in areas of the vehicle were packaging constraints require small, thin and flexible wiring harness assemblies to extend between electrical connectors. A typical flat flexible cable is comprised of a plurality of small gauge wires spaced apart from one another and surrounded by an insulating material. These flexible cables can be of various lengths depending on the application.
In order for the flat flexible cable to be electrically connected to a connector, conductive terminals have to be connected to each wire at an end of the cable. Because the wires in the flexible cable are very small gauge, the connecting methods used have to remove enough insulating material to provide sufficient surface area along the wire so that it can be securely connected to the terminal. A good connection between the wire and the terminal is required for good reliability, strength, and electrical properties.
Typical connection methods involve crimping or welding the terminal to the wire. Welding is preferred over crimping because the welding method provides greater surface area along the wire, thus, providing better reliability, strength and electrical properties. However, before the welding operation can be performed, the wires at the ends of the flat flexible cable must be stripped of their insulating coating. Currently, this stripping operation involves either an abrasion process or a laser process. Once the insulating coating has been stripped away, standard ultrasonic tooling can be used to weld the terminal to the exposed wire.
However, certain inefficiencies result from both the abrasive and laser processes for removing the insulating coating from the wires. Because the wires are thin, the abrasive process can damage or break the wires. Frequent wire damage or breakage can result in higher material costs and can increase assembly times due to removal and replacement of damaged cables. The laser stripping process is also undesirable because it is expensive.
Therefore, it is desirable to provide an inexpensive and efficient method of welding a terminal to a wire that does not damage or break the wire yet exposes sufficient surface area along the wire so that good reliability, strength, and electrical properties can be achieved when the terminals are connected to the wires in the cable.